diff --git a/vendor/github.com/gogo/protobuf/proto/properties.go b/vendor/github.com/gogo/protobuf/proto/properties.go
index c9e5fa0..62c5562 100644
--- a/vendor/github.com/gogo/protobuf/proto/properties.go
+++ b/vendor/github.com/gogo/protobuf/proto/properties.go
@@ -400,6 +400,15 @@
 	return sprop
 }
 
+type (
+	oneofFuncsIface interface {
+		XXX_OneofFuncs() (func(Message, *Buffer) error, func(Message, int, int, *Buffer) (bool, error), func(Message) int, []interface{})
+	}
+	oneofWrappersIface interface {
+		XXX_OneofWrappers() []interface{}
+	}
+)
+
 // getPropertiesLocked requires that propertiesMu is held.
 func getPropertiesLocked(t reflect.Type) *StructProperties {
 	if prop, ok := propertiesMap[t]; ok {
@@ -441,37 +450,40 @@
 	// Re-order prop.order.
 	sort.Sort(prop)
 
-	type oneofMessage interface {
-		XXX_OneofFuncs() (func(Message, *Buffer) error, func(Message, int, int, *Buffer) (bool, error), func(Message) int, []interface{})
-	}
-	if om, ok := reflect.Zero(reflect.PtrTo(t)).Interface().(oneofMessage); isOneofMessage && ok {
+	if isOneofMessage {
 		var oots []interface{}
-		_, _, _, oots = om.XXX_OneofFuncs()
-
-		// Interpret oneof metadata.
-		prop.OneofTypes = make(map[string]*OneofProperties)
-		for _, oot := range oots {
-			oop := &OneofProperties{
-				Type: reflect.ValueOf(oot).Type(), // *T
-				Prop: new(Properties),
-			}
-			sft := oop.Type.Elem().Field(0)
-			oop.Prop.Name = sft.Name
-			oop.Prop.Parse(sft.Tag.Get("protobuf"))
-			// There will be exactly one interface field that
-			// this new value is assignable to.
-			for i := 0; i < t.NumField(); i++ {
-				f := t.Field(i)
-				if f.Type.Kind() != reflect.Interface {
-					continue
+		switch m := reflect.Zero(reflect.PtrTo(t)).Interface().(type) {
+		case oneofFuncsIface:
+			_, _, _, oots = m.XXX_OneofFuncs()
+		case oneofWrappersIface:
+			oots = m.XXX_OneofWrappers()
+		}
+		if len(oots) > 0 {
+			// Interpret oneof metadata.
+			prop.OneofTypes = make(map[string]*OneofProperties)
+			for _, oot := range oots {
+				oop := &OneofProperties{
+					Type: reflect.ValueOf(oot).Type(), // *T
+					Prop: new(Properties),
 				}
-				if !oop.Type.AssignableTo(f.Type) {
-					continue
+				sft := oop.Type.Elem().Field(0)
+				oop.Prop.Name = sft.Name
+				oop.Prop.Parse(sft.Tag.Get("protobuf"))
+				// There will be exactly one interface field that
+				// this new value is assignable to.
+				for i := 0; i < t.NumField(); i++ {
+					f := t.Field(i)
+					if f.Type.Kind() != reflect.Interface {
+						continue
+					}
+					if !oop.Type.AssignableTo(f.Type) {
+						continue
+					}
+					oop.Field = i
+					break
 				}
-				oop.Field = i
-				break
+				prop.OneofTypes[oop.Prop.OrigName] = oop
 			}
-			prop.OneofTypes[oop.Prop.OrigName] = oop
 		}
 	}